Nairobi, Kenya (CNN) -- To anyone shopping at Nairobi's Westgate Mall, it would likely have seemed just another store.
But according to a Kenyan intelligence official, the small shop concealed an ominous secret. It was rented by the Al-Shabaabterrorists, or their associates, who within a year would carry out an attack on the upscale shopping mall.
The information -- revealed Friday to CNN by the source, who is close to the investigation into the attack -- suggests the Somalian terror organization had been planning the operation at least that long.
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